This invention generally relates to a guiding catheter for the direction of an intravascular device into a patient's coronary sinus and particularly to the direction of a mapping device into a cardiac vein draining into the coronary sinus for detecting electrical activity or signals causing or involved with arrhythmia from within the cardiac vein.
One of the most frequently used treatment modalities for arrhythmia is to destroy or damage heart tissue which causes the arrhythmia or involved with the arrhythmia by suitably heating the tissue, e.g. applying a laser beam or high frequency electrical energy (RF or microwave).
To be effective, the location of the tissue site causing or involved with the arrhythmia must be accurately determined in order to be able to contact a heart surface adjacent to the desired location with a tissue destroying device. A major problem of ablating the site of the origin of the signals or a conductive pathway with commercially available devices is that an excessive amount of good tissue is very frequently damaged or destroyed along with the arrhythmogenic site to ensure that the arrhythmia does not return. For example, the average arrhythmogenic site consists of about 1.4 cm.sup.2 of endocardial tissue, whereas a re-entrant site might be much larger. RF ablation techniques with commercially available devices produce lesions about 0.5 cm.sup.2 in diameter, so that it may be necessary to form several overlapping lesions in the region in order to completely ablate the area of interest and termination of the arrhythmia. If the arrhythmogenic or re-entrant site has not been accurately mapped, much good tissue surrounding the site will be unnecessarily damaged or destroyed to ensure termination of the arrhythmia.
A variety of methods have been used to detect electrical activity within a patient's heart to facilitate the mapping of electrical activity causing the arrhythmia. A number of U.S. Patents describe the use of elongated intravascular signal sensing devices which are advanced through the patient's vasculature until the distal portions of the sensing devices are disposed within a patient's heart chamber with one or more electrodes on the distal portion of the sensing device in contact with the endocardial lining. While this procedure is widely used, it does not always allow the site of arrhythmogenic signals to be accurately determined and frequently results in unnecessary damage to heart tissue which may already be in jeopardy.
Copending application Ser. No. 08/188,619, filed Jan. 27, 1994, now abanadoned, entitled INTRAVASCULAR SENSING DEVICE describes intravascular devices which can be advanced into a patient's coronary artery or cardiac vein where the device is used to detect electrical activity of the patient's heart.
While there are commercially available guiding catheters suitable for directing a variety of intravascular devices into a patient's coronary arteries, there are no devices available which allow for the rapid advancement of an intravascular device into a patient's coronary sinus and particularly into a cardiac vein draining into the coronary sinus.